Posted
by
kdawson
on Tuesday August 19, 2008 @03:56PM
from the moore-and-moore-tiny dept.

arcticstoat notes an announcement from IBM that, along with technology partners, they have produced the first working sample of a SRAM cell built on a 22nm fabrication process. According to the article, this represents the next generation after 32nm process chips and won't be in products for some years. "The technology was developed with several partners, including AMD, Toshiba, STMicroelectronics and Freescale, as well as the College of Nanoscale Science and Engineering, where IBM performs a lot of its semiconductor research. IBM says that the cell's development involved 'novel fabrication processes,' including high-NA immersion lithography..., high-K metal gate stacks, extremely thin silicide, damascene copper contacts, and advanced activation techniques."

I remember when they said 90nm was the limit of lithography. All the limits fall as there is a massive amount of money going into systems and methods to cheat the "limit". The real physical limit is a single atom width, at that point you can't go smaller, assuming there is a limit other than that single qualifier is dishonest because as with most of the other limits we have found ways to engineer around the "limit". Even if you think there is no way we could possibly have single atom paths you aren't considering the engineering advancement that could make such a thing possible including the use of materials other than silicon.

I did study electronic engineering, but it was 14 years ago and I'm not sure my answer's much better...

A popular on-line encyclopaedia says that Silicon has a Van der Waals radius (the size if we pretend the atom is a solid sphere) of 210pm - over 100 times less than the 22nm process. If you also count the need to dope the silicon p-type or n-type, grow layers of insulator like silicon dioxide and avoid quantum stuff that I never really understood, then I'd guess at a lower limit of around 25 or so atoms for a workable structure. Let's call it 5nm - hey that's a factor of 4x less than 22nm like you said!

From a different point of view, I've seen papers by groups who have been fabricating structures at the sub-10nm region. Again, perhaps it can be pushed to 5nm.

Beyond that we'll need to think about alternatives - making electrons move faster, like strained silicon does, or giving up silicon for something like diamond (so we can have super-computer bling:)

If the silicon process shrinks every 2-3 years, we'll hit the limit about 10 years. But they said that 10 years ago too!